Candidate Barack Obama had no better buddy on the 2008 primary trail than Missouri Sen. Claire McCaskill, who was feared — and a little hated — by Hillary Clinton’s campaign for being Obama’s most effective female surrogate.

McCaskill still likes Obama, but like many other former high-profile Obama surrogates from 2008, she’s not expected to reprise her starring proxy role in 2012.

McCaskill has publicly parted ways with Obama on several major issues, including entitlement reform, and needs to tend to her own challenging reelection campaign, made all the tougher by controversy about reimbursements for flights on her family’s private plane.

“She’s basically out of the picture for us this time around,” said an Obama ally who considers McCaskill’s absence — and the difficulty of replacing high-impact supporters like her — a potential problem.

“We need more defenders,” the ally said. Obama “is spending too much time communicating about himself for himself. ... I think we’ve only had a couple of people out there speaking for us over the last two years, and clearly, that has to change.”

Obama’s team is confident it will eventually line up plenty of support, especially when GOP front-runners emerge, creating a clearer contrast to frame his campaign. But it won’t be easy.

Kick-starting a campaign after two years in the White House means old friends tend to become less friendly after compromises and disappointments — and finding validators who haven’t drawn an administration paycheck becomes more difficult. (See also: Obama's poll numbers)

And the role of surrogates in 2012 will be fundamentally different than last time — less about introducing Obama to the public and more about explaining health care reform, the stimulus, two-and-half wars and the flagging economy to anxious voters.

But the surrogate hunt is especially hard for Obama, who has relied on an unusually small stable of trusted representatives and demands tight control over his message and image. The insular modus operandi has frequently ticked off outside-the-bubble Democrats, never the easiest group to herd, even in the most tranquil times.

“Obama isn’t the insurgent anymore, and neither are surrogates like McCaskill or [South Carolina Democratic Rep. Jim] Clyburn, so there’s a tension there as they all deal with their own politics,” said George Atherton, a professor at The George Washington University’s Graduate School of Political Management and a veteran Democratic consultant.

“It’s not difficult for Obama to mobilize the people who work for him like the Cabinet, but it will be interesting to see if he can get real value out of outside people like he did in 2008,” he added.

One veteran Democrat and reliable cable-news show advocate for Obama faults the White House’s handling of messaging.

“A lot of this had to do with the arrogance the Obama people had initially,” the Democrat said. “No one was really in charge of coordinating what we did. ... No one really communicated with us on a consistent basis. It’s gotten better over the last year, but they still have a way to go.”

Through no fault of Obama’s, many effective surrogates are simply out of the picture or are now cast in diminished roles: Sen. Ted Kennedy, whose primary endorsement was a watershed in the 2008 primary, died in August 2009; Reps. Artur Davis of Alabama and Robert Wexler of Florida, who wooed black and Jewish voters away from Clinton, resigned their seats; and two key allies in Midwestern battlegrounds, Ohio Gov. Ted Strickland and Iowa Gov. Chet Culver, lost tough reelection bids in 2010.

Obama’s newly installed 2012 campaign manager, Jim Messina, has made recruiting surrogates a priority as he sets up the president’s reelection headquarters in Chicago, according to several Democrats close to the campaign. Messina, they said, is focused on restocking the arsenal with state-level surrogates, like McCaskill, who can lend him credibility and political cover among women, minority groups and independents in battleground states.

That job seems easiest if Mitt Romney becomes the Republican nominee: Gov. Deval Patrick, one of Obama’s closest allies outside Washington, has already begun hammering his predecessor in the governor’s mansion for attacking Obama’s health reform plan after passing a similar statewide measure in Massachusetts.

“It’s difficult to see how an acknowledged success in Massachusetts can become a presumptive failure nationally,’’ Patrick quipped last week in what would be a theme against Romney. “But you know, this is more about politics than policy.”

The campaign faces a tougher task if the GOP taps a nominee from a state in which Obama’s approval rating is underwater and Democrats are reluctant to be associated with the president.

Messina and company have begun compiling a list of possible in-state surrogates who can attack Indiana Gov. Mitch Daniels or former Minnesota Gov. Tim Pawlenty, including former Sen. Evan Bayh and a bevy of state-level officials.

Other potential stars are rising — each conveniently not on the ballot in 2012: The senatorial Udalls — Colorado’s Mark and New Mexico’s Tom — and moderate Virginia Democratic Sen. Mark Warner, who could evolve into a Kaine stand-in despite a somewhat arm’s-length relationship with Team Obama.

Still, the Obama campaign’s core national strategy relies on several well-known defenders who have been, until recently, on the payroll: former senior adviser David Axelrod, former press secretary Robert Gibbs and Anita Dunn, a former White House communications director who still advises Obama.

That circle is widening, but is experiencing growing pains.

Last month, White House senior adviser David Plouffe, according to party sources, had more or less settled on former Ohio Gov. Ted Strickland to replace Kaine as head of the Democratic National Committee, despite an eleventh-hour push for Los Angeles Mayor Antonio Villaraigosa.

At that point, several women close to Obama, including senior adviser Valerie Jarrett, made the case for Florida Rep. Debbie Wasserman Schultz (D-Fla.), one of Obama’s top surrogates on the cable-TV circuit.

After a brief but intense internal debate over a joint chairmanship, the group opted for Wasserman Schultz, who can help Obama with Jewish donors, Sunshine State voters and above all, women, creating a powerful one-two punch with first lady Michelle Obama.

White House communications director Dan Pfeiffer disputed this version of events, describing it as “very inaccurate,” though other Democratic sources stood by its accuracy.

The discussions are frank, and Pfeiffer has made an effort in recent months to elicit the group’s advice, instead of distributing marching orders and talking points, said some of the participants, who give him high marks outside for shoring up the administration’s sometimes rocky relationship with this cacophonous talking-head class.

At the most recent meeting, Obama himself stuck his head in the room to issue a “thanks, guys,” to the group as Ken Baer, a spokesman in the Office of Management and Budget, was going over the finer points of the president’s deficit reduction plan.

Plouffe, sources said, has instructed his staff to be far more aggressive about deploying Cabinet officers to explain Obama’s policies and respond to natural disasters, such as the Mississippi floods. “We’re in the game now,” said a Cabinet member who was active in Obama’s 2008 campaign. “That wasn’t the case before David came back.”

Even with those resources deployed, Obama faces the reality that almost every White House incumbent must eventually deal with: Politicians in his own party in vast swaths of battleground territory simply don’t want him around next year, in marked contrast to 2006 and 2008, when Obama the hottest national draw for local pols.

Even Kaine — who has no plans to distance himself from Obama, whom he considers a friend — doesn’t have the time to campaign for the president or the inclination to expose himself to GOP candidate George Allen’s claims that Kaine’s a liberal Obama clone.

In other parts of the country, where Obama is even less popular, some Democrats might even become anti-surrogates — as West Virginia Democratic Sen. Joe Manchin did in 2010, damning the White House with faint praise and criticizing Obama policies.

Houston-based Democratic consultant Marc Campos predicts that Obama’s effort to make gains with Hispanics in Texas will take a hit if the party’s Senate candidate — who could be retired Gen. Ricardo Sanchez — turns against Obama for self-preservation.

“That would really undermine everything Obama is trying to do down here,” Campos said.